Messages in this thread | | | Subject | Re: [PATCH 10/35] irqchip/gic-v4.1: VPE table (aka GICR_VPROPBASER) allocation | From | Zenghui Yu <> | Date | Fri, 27 Sep 2019 09:59:16 +0800 |
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On 2019/9/26 23:57, Marc Zyngier wrote: > On 26/09/2019 16:19, Zenghui Yu wrote: >> On 2019/9/25 22:41, Marc Zyngier wrote: >>> >>> Indeed. The whole idea is that ITSs and RDs can share a vPE table if >>> they are in the same affinity group (such as a socket, for example). >>> This is what is missing from v4.0 where the ITS knows about vPEs, but >>> doesn't know about residency. With that in place, the HW is able to do a >>> lot more for us. >> >> Thanks for your education! >> >> I really want to know *how* does GICv4.1 ITS know about the vPE >> residency (in hardware level)? > > Hey, I'm a SW guy, I don't design the hardware! ;-) > >> I can understand that Redistributor can easily achieve it by >> VPENDBASER's Valid and vPEID field. And it's necessary for ITS to >> know the residency so that it can determine whether it's appropriate >> to trigger default doorbell for vPE. But I have no knowledge about >> how can it be achieved in hardware details. > > My take is that the RD and the ITS can communicate over the shared > table, hence my remark above about SVPET==0. But as I said, I'm not a HW > guy.
;-) I should have asked our GIC engineers for these things.
Thanks, zenghui
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